cleanup example config file + Squashed commit of the following:

commit c36b66dc952dfff91043ecbca56cf3f1f8f00703
Merge: 240d7bf f4cf934
Author: Michael DeHaan <michael@ansibleworks.com>
Date:   Tue Jun 18 13:04:51 2013 -0400

    Merge branch 'unevaluated-vars' of git://github.com/lorin/ansible into lorin_undefined

    Conflicts:
    	lib/ansible/runner/__init__.py

commit f4cf93436767f73b62a16067ab5e628830045896
Merge: 2531440 07a1365
Author: Lorin Hochstein <lorin@nimbisservices.com>
Date:   Thu Jun 6 11:07:41 2013 -0400

    Merge branch 'devel' into unevaluated-vars

commit 253144045cbafd7d72836f1017c62ac4ba623186
Author: Lorin Hochstein <lorin@nimbisservices.com>
Date:   Thu Jun 6 11:06:37 2013 -0400

    Fail template from file on undefined vars

    If config option is set, raise an exception if templating from a
    file and a variable is undefined.

commit aecb71d8b75257f0f3e11a9b176fc3737aecef8d
Author: Lorin Hochstein <lorin@nimbisservices.com>
Date:   Wed Jun 5 17:12:12 2013 -0400

    Add fail_on_undefined flag

    Add a fail_on_undefined flag to the template and template_from_string methods.

    If this flag is true, then re-raise the ninja2.excpetions.UndefinedError instead of
    swallowing it.

commit cbb1808f0585f01536240aee05a1bfd06c4b4647
Merge: d4bbf49 41425fb
Author: Lorin Hochstein <lorin@nimbisservices.com>
Date:   Wed Jun 5 16:14:12 2013 -0400

    Merge branch 'devel' into unevaluated-vars

commit d4bbf492b0b63c789d66ab60d0ec634d100fca82
Author: Lorin Hochstein <lorin@nimbisservices.com>
Date:   Mon Jun 3 19:46:13 2013 -0400

    template: Raise UndefinedError exception

    In template_from_string, raise an undefined error if it occurs.

    Have the caller catch it and throw an AnsibleUndefinedVariable

commit c94780280515f1f3756fdc429b2b1e87b365e9b7
Merge: 8d919d6 be33bcf
Author: Lorin Hochstein <lorin@nimbisservices.com>
Date:   Mon Jun 3 10:09:43 2013 -0400

    Merge branch 'devel' into unevaluated-vars

commit 8d919d6c97b28a42f47ca7248c542695baf6175f
Merge: 0f68ad8 b8630d2
Author: Lorin Hochstein <lorin@nimbisservices.com>
Date:   Thu May 30 16:27:48 2013 -0400

    Merge branch 'devel' into unevaluated-vars

commit 0f68ad8193ac17488e339a258f8c63fdae399c26
Author: Lorin Hochstein <lorin@nimbisservices.com>
Date:   Thu May 30 14:32:03 2013 -0400

    Optionally fail task on undefined variables

    This patch introduces a new configuration option called
    error_on_undefined_vars, which defaults to false.

    If this option is set to true, then a task which has unevaluated
    variables in its arguments will fail instead of running. Output looks
    like this:

        TASK: [set rabbitmq password] *************************************************
        fatal: [10.20.0.7] => Undefined variables: rabbitmq_user, rabbitmq_password

examples/ansible.cfg

@@ -1,138 +1,75 @@
-# config file for ansible -- http://ansible.github.com
+# config file for ansible -- http://ansibleworks.com/
-#
+# ==================================================
-# nearly all parameters can be overridden in ansible-playbook or with command line flags
+
-# ansible will read ~/.ansible.cfg, ansible.cfg in the current working directory or
+# nearly all parameters can be overridden in ansible-playbook 
+# or with command line flags. ansible will read ~/.ansible.cfg, 
+# ansible.cfg in the current working directory or
 # /etc/ansible/ansible.cfg, whichever it finds first
 
 [defaults]
 
-# location of inventory file, eliminates need to specify -i
+# some basic default values...
 
-hostfile = /etc/ansible/hosts
+hostfile       = /etc/ansible/hosts
+library        = /usr/share/ansible
+remote_tmp     = $HOME/.ansible/tmp
+pattern        = *
+forks          = 5
+poll_interval  = 15
+sudo_user      = root
+#ask_sudo_pass = True
+#ask_pass      = True
+transport      = paramiko
+remote_port    = 22
 
-# location of ansible library, eliminates need to specify --module-path
+# change this for alternative sudo implementations
+sudo_exe       = sudo
 
-library = /usr/share/ansible
+# what flags to pass to sudo
-
-# default module name used in /usr/bin/ansible when -m is not specified
-
-module_name = command
-
-# location for ansible log file.  If set, will store output from ansible 
-# and ansible-playbook.  If enabling, you may wish to configure
-# logrotate.
-
-#log_path = /var/log/ansible.log
-
-# home directory where temp files are stored on remote systems.  Should
-# almost always contain $HOME or be a directory writeable by all users
-
-remote_tmp = $HOME/.ansible/tmp
-
-# the default pattern for ansible-playbooks ("hosts:")
-
-pattern = *
-
-# the default number of forks (parallelism) to be used.  Usually you
-# can crank this up.
-
-forks=5
-
-# the timeout used by various connection types.  Usually this corresponds
-# to an SSH timeout
-
-timeout=10
-
-# when using --poll or "poll:" in an ansible playbook, and not specifying
-# an explicit poll interval, use this interval
-
-poll_interval=15
-
-# when specifying --sudo to /usr/bin/ansible or "sudo:" in a playbook,
-# and not specifying "--sudo-user" or "sudo_user" respectively, sudo
-# to this user account
-
-sudo_user=root
-
-# the following forces ansible to always ask for the sudo password (instead of having
-# to add -K to the commandline). Or you can use the environment variable (ANSIBLE_ASK_SUDO_PASS)
-
-#ask_sudo_pass=True
-
-# the following forces ansible to always ask for the ssh-password (-k)
-# can also be set by the environment variable ANSIBLE_ASK_PASS
-
-#ask_pass=True
-
-# connection to use when -c <connection_type> is not specified
-
-transport=paramiko
-
-# remote SSH port to be used when --port or "port:" or an equivalent inventory
-# variable is not specified.
-
-remote_port=22
-
-# if set, always run /usr/bin/ansible commands as this user, and assume this value
-# if "user:" is not set in a playbook.  If not set, use the current Unix user
-# as the default
-
-#remote_user=root
-
-# the default sudo executable. If a sudo alternative with a sudo-compatible interface
-# is used, specify its executable name as the default
-
-sudo_exe=sudo
-
-# the default flags passed to sudo
 # sudo_flags=-H
 
-# all commands executed under sudo are passed as arguments to a shell command
+# SSH timeout
-# This shell command defaults to /bin/sh
+timeout      = 10
-# Changing this helps the situation where a user is only allowed to run
-# e.g. /bin/bash with sudo privileges
 
+# default user to use for playbooks if user is not specified
+# (/usr/bin/ansible will use current user as default)
+remote_user=root
+
+# logging is off by default unless this path is defined
+# if so defined, consider logrotate
+# log_path = /var/log/ansible.log
+
+# default module name for /usr/bin/ansible
+module_name = command
+
+# use this shell for commands executed under sudo
+# you may need to change this to bin/bash in rare instances
+# if sudo is constrained
 # executable = /bin/sh
 
-# how to handle hash defined in several places
+# if inventory variables overlap, does the higher precedence one win
-# hash can be merged, or replaced
+# or are hash values merged together?  The default is 'replace' but
-# if you use replace, and have multiple hashes named 'x', the last defined
+# this can also be set to 'merge'.
-# will override the previously defined one
-# if you use merge here, hash will cumulate their keys, but keys will still
-# override each other
-# replace is the default value, and is how ansible always handled hash variables
-#
 # hash_behaviour=replace
 
 # How to handle variable replacement - as of 1.2, Jinja2 variable syntax is
 # preferred, but we still support the old $variable replacement too.
-# If you change legacy_playbook_variables to no then Ansible will no longer
+# Turn off ${old_style} variables here if you like.
-# try to do replacement on $variable style variables.
-#
 # legacy_playbook_variables=yes
 
-# if you need to use jinja2 extensions, you can list them here
+# list any Jinja2 extensions to enable here:
-# use a coma to separate extensions, e.g. :
 # jinja2_extensions=jinja2.ext.do,jinja2.ext.i18n
-# no extensions are loaded by default
-
-#jinja2_extensions=
-
-# if set, always use this private key file for authentication, same as if passing
-# --private-key to ansible or ansible-playbook
 
+# if set, always use this private key file for authentication, same as 
+# if passing --private-key to ansible or ansible-playbook
 #private_key_file=/path/to/file
 
-# format of string $ansible_managed available within Jinja2 templates, replacing
+# format of string {{ ansible_managed }} available within Jinja2 
-# {file}, {host} and {uid} with template filename, host and owner respectively.
+# templates indicates to users editing templates files will be replaced.
-# The resulting string is passed through strftime(3) so it may contain any
+, replacing {file}, {host} and {uid} and strftime codes with proper values.
-# time-formatting specifiers.
-#
-# Example: ansible_managed = DONT TOUCH {file}: call {uid} at {host} for changes
 ansible_managed = Ansible managed: {file} modified on %Y-%m-%d %H:%M:%S by {uid} on {host}
 
-# additional plugin paths for non-core plugins
+# set plugin path directories here, seperate with colons
-
 action_plugins     = /usr/share/ansible_plugins/action_plugins
 callback_plugins   = /usr/share/ansible_plugins/callback_plugins
 connection_plugins = /usr/share/ansible_plugins/connection_plugins
@@ -140,24 +77,23 @@ lookup_plugins     = /usr/share/ansible_plugins/lookup_plugins
 vars_plugins       = /usr/share/ansible_plugins/vars_plugins
 filter_plugins     = /usr/share/ansible_plugins/filter_plugins
 
-# set to 1 if you don't want cowsay support. Alternatively, set ANSIBLE_NOCOWS=1
+# don't like cows?  that's unfortunate.
-# in your environment
+# set to 1 if you don't want cowsay support or export ANSIBLE_NOCOWS=1 
-# nocows           = 1
+# nocows = 1
 
 [paramiko_connection]
 
-# nothing to configure yet
+# nothing configurable yet
 
 [ssh_connection]
 
-# if uncommented, sets the ansible ssh arguments to the following.  Leaving off ControlPersist
+# ssh arguments to use
-# will result in poor performance, so use transport=paramiko on older platforms rather than
+# Leaving off ControlPersist will result in poor performance, so use 
-# removing it
+# paramiko on older platforms rather than removing it
-
 ssh_args=-o ControlMaster=auto -o ControlPersist=60s -o ControlPath=/tmp/ansible-ssh-%h-%p-%r
 
-# the following makes ansible use scp if the connection type is ssh (default is sftp)
+# if True, make ansible use scp if the connection type is ssh 
-
+# (default is sftp)
 #scp_if_ssh=True
 
 

lib/ansible/constants.py

@@ -110,6 +110,8 @@ ANSIBLE_NOCOWS                 = get_config(p, DEFAULTS, 'nocows', 'ANSIBLE_NOCO
 ANSIBLE_SSH_ARGS               = get_config(p, 'ssh_connection', 'ssh_args', 'ANSIBLE_SSH_ARGS', None)
 ZEROMQ_PORT                    = int(get_config(p, 'fireball', 'zeromq_port', 'ANSIBLE_ZEROMQ_PORT', 5099))
 
+DEFAULT_UNDEFINED_VAR_BEHAVIOR = get_config(p, DEFAULTS, 'error_on_undefined_vars', 'ANSIBLE_ERROR_ON_UNDEFINED_VARS', False)
+
 # non-configurable things
 DEFAULT_SUDO_PASS         = None
 DEFAULT_REMOTE_PASS       = None

lib/ansible/errors.py

@@ -32,3 +32,6 @@ class AnsibleConnectionFailed(AnsibleError):
 
 class AnsibleYAMLValidationFailed(AnsibleError):
     pass
+
+class AnsibleUndefinedVariable(AnsibleError):
+    pass

lib/ansible/runner/__init__.py

@@ -30,6 +30,7 @@ import base64
 import sys
 import shlex
 import pipes
+import jinja2
 
 import ansible.constants as C
 import ansible.inventory
@@ -128,7 +129,8 @@ class Runner(object):
         check=False,                        # don't make any changes, just try to probe for potential changes
         diff=False,                         # whether to show diffs for template files that change
         environment=None,                   # environment variables (as dict) to use inside the command
-        complex_args=None                   # structured data in addition to module_args, must be a dict
+        complex_args=None,                  # structured data in addition to module_args, must be a dict
+        error_on_undefined_vars=C.DEFAULT_UNDEFINED_VAR_BEHAVIOR # ex. False
         ):
 
         if not complex_args:
@@ -164,6 +166,7 @@ class Runner(object):
         self.environment      = environment
         self.complex_args     = complex_args
         self.module_with_list = False
+        self.error_on_undefined_vars = error_on_undefined_vars
 
         self.callbacks.runner = self
 
@@ -576,8 +579,12 @@ class Runner(object):
             tmp = self._make_tmp_path(conn)
 
         # render module_args and complex_args templates
-        module_args = template.template(self.basedir, module_args, inject)
+        try:
-        complex_args = template.template(self.basedir, complex_args, inject)
+            module_args = template.template(self.basedir, module_args, inject, fail_on_undefined=self.error_on_undefined_vars)
+            complex_args = template.template(self.basedir, complex_args, inject, fail_on_undefined=self.error_on_undefined_vars)
+        except jinja2.exceptions.UndefinedError, e:
+            raise errors.AnsibleUndefinedVariable("Undefined variables: %s" % str(e))
+
 
         result = handler.run(conn, tmp, module_name, module_args, inject, complex_args)
 

lib/ansible/utils/template.py

@@ -295,7 +295,7 @@ def legacy_varReplace(basedir, raw, vars, lookup_fatal=True, depth=0, expand_lis
 
 # TODO: varname is misnamed here
 
-def template(basedir, varname, vars, lookup_fatal=True, depth=0, expand_lists=True, convert_bare=False):
+def template(basedir, varname, vars, lookup_fatal=True, depth=0, expand_lists=True, convert_bare=False, fail_on_undefined=False):
     ''' templates a data structure by traversing it and substituting for other data structures '''
 
     if convert_bare and isinstance(varname, basestring):
@@ -305,7 +305,7 @@ def template(basedir, varname, vars, lookup_fatal=True, depth=0, expand_lists=Tr
 
     if isinstance(varname, basestring):
         if '{{' in varname or '{%' in varname:
-            varname = template_from_string(basedir, varname, vars)
+            varname = template_from_string(basedir, varname, vars, fail_on_undefined)
         if not '$' in varname:
             return varname
 
@@ -398,6 +398,8 @@ class J2Template(jinja2.environment.Template):
 def template_from_file(basedir, path, vars):
     ''' run a file through the templating engine '''
 
+    fail_on_undefined = C.DEFAULT_UNDEFINED_VAR_BEHAVIOR
+
     from ansible import utils
     realpath = utils.path_dwim(basedir, path)
     loader=jinja2.FileSystemLoader([basedir,os.path.dirname(realpath)])
@@ -409,6 +411,8 @@ def template_from_file(basedir, path, vars):
     environment = jinja2.Environment(loader=loader, trim_blocks=True, extensions=_get_extensions())
     environment.filters.update(_get_filters())
     environment.globals['lookup'] = my_lookup
+    if fail_on_undefined:
+        environment.undefined = StrictUndefined
 
     try:
         data = codecs.open(realpath, encoding="utf8").read()
@@ -455,13 +459,16 @@ def template_from_file(basedir, path, vars):
     # This line performs deep Jinja2 magic that uses the _jinja2_vars object for vars
     # Ideally, this could use some API where setting shared=True and the object won't get
     # passed through dict(o), but I have not found that yet.
-    res = jinja2.utils.concat(t.root_render_func(t.new_context(_jinja2_vars(basedir, vars, t.globals), shared=True)))
+    try:
+        res = jinja2.utils.concat(t.root_render_func(t.new_context(_jinja2_vars(basedir, vars, t.globals), shared=True)))
+    except jinja2.exceptions.UndefinedError, e:
+        raise errors.AnsibleUndefinedVariable("Undefined variables: %s" % str(e))
 
     if data.endswith('\n') and not res.endswith('\n'):
         res = res + '\n'
     return template(basedir, res, vars)
 
-def template_from_string(basedir, data, vars):
+def template_from_string(basedir, data, vars, fail_on_undefined=False):
     ''' run a string through the (Jinja2) templating engine '''
 
     try:
@@ -497,6 +504,9 @@ def template_from_string(basedir, data, vars):
         res = jinja2.utils.concat(t.root_render_func(t.new_context(_jinja2_vars(basedir, vars, t.globals), shared=True)))
         return res
     except jinja2.exceptions.UndefinedError:
+        if fail_on_undefined:
+            raise
+        else:
         # this shouldn't happen due to undeclared check above
-        return data
+            return data